D'Ansit

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D'Ansit
General and classification
other names

D'Ansit or Dansit

chemical formula Na 21 Mg [Cl 3 | (SO 4 ) 10 ]
Mineral class
(and possibly department) 		Sulphates, Selenates, Tellurates, Chromates, Molybdates and Wolframates
System no. to Strunz
and to Dana 		7.BC.05 ( 8th edition : VI / B.04)
01/30/10/01
Crystallographic Data
Crystal system cubic
Crystal class ; symbol cubic-hexakistrahedral; 4 3 m
Room group (no.) I 4 3 d (No. 220)
Lattice parameters a  = 15.91  Å
Formula units Z  = 4
Frequent crystal faces {211}, {2 1 1}
Twinning polysynthetic twins
Physical Properties
Mohs hardness 2.5 to 3
Density (g / cm 3 ) measured: 2.63 to 2.655; calculated: 2.60
Cleavage not defined
Break ; Tenacity not defined
colour colorless, yellow, light brown
Line color White
transparency translucent
shine Greasy shine
Other properties
Chemical behavior soluble in water

D'Ansit is a very rare mineral from the mineral class of "sulfates (and relatives)" (see classification ). It crystallizes in the cubic crystal system with the chemical composition Na 21 Mg [Cl 3 | (SO 4 ) 10 ], so it is a sodium - magnesium sulfate with additional chlorine ions .

So far, D'Ansit could only be found in the form of inclusions in Blödit . In its pure form, D'Ansit is colorless and transparent. However, due to multiple refraction due to lattice construction defects or polycrystalline formation, it can also appear white and, due to foreign admixtures, take on a yellow or light brown color, the transparency decreasing accordingly. Synthetic D'Ansit crystals have a tetrahedral habit with a maximum edge length of 0.3 millimeters and a fat-like sheen on the surfaces.

D'Ansit is the Mg analogue of the minerals D'Ansit- (Fe) Na 21 Fe [Cl 3 | (SO 4 ) 10 ] and D'Ansit- (Mn) Na 21 Mn [Cl 3 | ( SO 4 ) 10 ].

Special properties

D'Ansit is easily soluble in water and must therefore be stored away from moisture.

Etymology and history

The mineral was first discovered in the salt pits near Hall in Tirol in Austria and briefly described in 1909 by R. Gorgey, who, however, gave the mineral no name. In 1958, H. Autenrieth and G. Braune succeeded in producing the mineral synthetically and named it in their publication as D'Ansit after the German mineralogist Jean D'Ans (1881–1969). The natural existence of D'Ansit was confirmed finally Shi Nicheng and Ma Zhesheng that the mineral cores from 1972 tertiary layers of salt deposits of Jianghan found in China.

classification

In the outdated, but partly still in use, 8th edition of the mineral classification according to Strunz , the D'Ansit belonged to the mineral class of "sulfates, chromates, molybdates and wolframates" and there to the department of "anhydrous sulfates, with foreign anions ", where it belongs together Ye'elimit formed the unnamed group VI / B.04 .

The 9th edition of Strunz's mineral systematics, which has been in effect since 2001 and is used by the International Mineralogical Association (IMA), assigns D'Ansit to the extended class of "sulfates, selenates, tellurates, chromates, molybdates and wolframates", but also there the section of "sulfates (selenates, etc.) with additional anions, without H 2 O". This is further subdivided according to the relative size of the cations involved , so that the mineral can be found according to its composition in the sub-section "With medium-sized and large cations", where it is the only member of the unnamed group 7.BC.05 .

The systematics of minerals according to Dana , which is mainly used in the English-speaking world , assigns the D'Ansit to the class of “sulfates, chromates and molybdates” and there to the “anhydrous sulfates with hydroxyl or halogen” class. Here he is the only member / together with in the unnamed group 01/30/10 within the subsection “Anhydrous sulfates with hydroxyl or halogen and (AB) m (XO 4 ) p Z q , with m: p> 2: 1” .

Education and Locations

D'Ansit forms as a rare component in marine evaporite - deposits , where he, among others, in paragenesis with bloedite , Thenardite and vanthoffite occurs.

So far (as of 2013) the mineral is known from its type locality Hall in Tirol only from the Jianghan salt deposit in the Chinese province of Hubei.

Crystal structure

D'Ansit crystallizes cubically in the space group I 4 3 d (space group no. 220) with the lattice parameter a  = 15.91  Å and 4 formula units per unit cell .

See also

literature

Web links

Individual evidence

  1. ↑ a b c d e Hugo Strunz , Ernest H. Nickel: Strunz Mineralogical Tables . 9th edition. E. Schweizerbart'sche Verlagbuchhandlung (Nägele and Obermiller), Stuttgart 2001, ISBN 3-510-65188-X , p.  372 .
  2. ↑ a b D'Ansite , In: John W. Anthony, Richard A. Bideaux, Kenneth W. Bladh, Monte C. Nichols (Eds.): Handbook of Mineralogy, Mineralogical Society of America , 2001 ( PDF 63.5 kB )
  3. ↑ Webmineral - DAnsite
  4. ^ Carl Hintze : New minerals and new mineral names (with supplements, corrections and additions). Walter de Gruyter, Berlin 1968, p. 84 ( available online in the Google book search)
  5. ^ IMA / CNMNC List of Mineral Names; October 2013 (PDF 1.5 MB)
  6. ↑ Shi Nicheng and Ma Zhesheng (1987): Crystal structure of d'ansite. In: Kexue Tongbao. Volume 32 (7), pp. 478-481 ( short description available online at csb.scichina.com ( Memento from 7 January 2014 in the Internet Archive ))
  7. ↑ Find location list for D'Ansit at the Mineralienatlas and at Mindat